1. Field of the Invention
This invention relates to an automatic door driving system and, more particularly, to an automatic driving system, which permits an automatic door to be opened and closed electrically in case of emergency such as the occurrence of a fire or when power supply is stopped and can also control the opening and closing of the automatic door in accordance with the status of an emergency.
2. Description of the Prior Art
In an automatic door driving system, the automatic door usually can be opened and closed for refuge or fire prevention in case of an emergency such as the occurrence of a fire or when power supply is stopped.
An emergency automatic door driving system for mechanically opening or closing an automatic door in case of emergency is disclosed in Japanese Patent Publication Sho 60-16552.
In the disclosed emergency automatic door driving system, a driven pulley, around which is a chain or the like for driving the automatic door, is provided with a reversely rotatable shaft with a spiral leaf spring rewindingly wound thereon. When an electric power is interrupted in case of emergency, a solenoid is excited so that the driven pulley and the shaft are connected to each other, whereby the automatic door is emergency-opened or -closed by the rewinding force of the spiral leaf spring.
In such a mechanical emergency automatic door driving system, however, the automatic door is mechanically opened or closed by the rewinding force of the spiral leaf spring. Therefore, the door is only opened or closed, i.e., it is driven only in one direction. In addition, it is impossible to control the speed or pattern of opening or closing the door.